Boot Release With Key Unresponsive

[Ruofdez]

Central locking for doors works fine and roof goes up and down with the key without issue but the boot release is really unresponsive. Usually it will work with enough persistence but usually takes lots of presses and patience so end up doing it from in the car.

I will get the other key to rule that out but seems unlikely where the other functions work fine on it unless it’s the button itself on the key I suppose.

Did search the forum but most people seem to be referring to the boot lid not opening unless the doors are unlocked and that’s not the issue here.

Any ideas would be really appreciated. Thanks.

 

[Ewazix]

Check the other key, but given that it functions on the internal button it's quite possibly the GM5 central locking module. The relays give out and you develop intermittent unlocking problems from the key, usually on doors but also the boot. I've fixed a couple and did a write up on the pre-facelift, but the facelift is the basically the same it's just slightly easier to access the module behind the the glove box. https://z4-forum.com/forum/viewtopic.php?t=102586

Important things to note:
The modules are coded to your car's ECU so a second-hand unit needs to be coded which is a PITA and requires specialist software.
You can replace the relays, which I considered, but the boards are notoriously easy to damage when unsoldering pins and for the relatively cheap cost of sending away for a repair isn't usually worth it. Several places repair with very quick turn-arounds.
The car can technically be driven with the GM5 removed but locking and several other functions (like wipers, roof etc I think) obviously won't work.
It's fiddly but not a difficult or expensive DIY job, but dealers will pull your trousers down.

 

[Ruofdez]

That’s some really useful info, thank you very much for that. Other key was the same earlier so looks as if you’re right about gm5. I can live without the remote boot release always working but will try and get it sorted out when I get a chance. If the problem ends up affecting the doors that would obviously be a much bigger problem!

 

[Ewazix]

That’s some really useful info, thank you very much for that. Other key was the same earlier so looks as if you’re right about gm5. I can live without the remote boot release always working but will try and get it sorted out when I get a chance. If the problem ends up affecting the doors that would obviously be a much bigger problem!

The GM5 thing can come-and-go sometimes dependant on temperature or who knows what?